Methods of reducing trimethylamine

ABSTRACT

Absorbent materials configured to sequester trimethylamine (TMA), absorbent articles made therefrom, related methods of use, methods of measuring a reduction of free TMA, and related methods of making absorbent articles are described.

BACKGROUND

Trimethylamine (TMA) is a chemical that has a strong, fishy odor even atlow concentrations and is responsible for the fishy odor symptomatic ofbacterial vaginosis.

An increase in pH of the vaginal environment is common during andfollowing menstruation. Vaginal pH is usually 4-4.5; however, duringmenstruation vaginal pH can increase to 6.6. This increase in pH canencourage an overgrowth of anaerobic bacteria, sometimes resulting in anincrease in the amount of TMA released from the more alkalineenvironment of the vagina.

Feminine hygiene products, such as sanitary pads, are products commonlyused to absorb menstrual fluids, spotting, and urinary incontinenceleakage. Because these products absorb fluids that may be malodorous(such as those that include TMA), are held close to the body withminimal air flow and are worn for several hours, malodor can becomeconcentrated in these products. Therefore, TMA is a chemical of highinterest in odor control for feminine hygiene products.

Currently, absorbent hygiene products promoted for odor control do sousing fragrance, anti-bacterial properties, activated charcoal, or “OdorLock” technology. However, conventional absorbent hygiene products donot specifically address malodors associated with TMA, such as bysequestration of TMA.

TMA is also associated with meat products, particularly fish products.Bacteria and fish enzymes convert TMA oxide present in fish into TMA.Absorbent pads included in meat packaging absorb meat juices and otherliquids associated with meat products. However, conventional absorbentpads for meat packaging do not specifically sequester TMA or otherwisereduce TMA malodors associated with meat products.

Accordingly, there is a long-felt need for absorbent products that bothabsorb liquid and sequester TMA, thereby reducing TMA malodors. Thepresent disclosure seeks to fulfill these needs and provides furtherrelated advantages.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features ofthe claimed subject matter, nor is it intended to be used as an aid indetermining the scope of the claimed subject matter.

In an aspect, the present disclosure provides a method of reducing freetrimethylamine (“TMA”) comprising contacting a TMA molecule with anabsorbent material comprising a cellulosic fiber matrix and a carboxylicacid coupled to the cellulosic fiber matrix, wherein the reduction infree TMA is relative to a control.

In another aspect the present disclosure provides a method ofsequestering TMA molecules comprising contacting the TMA molecules withan absorbent material comprising a cellulosic fiber matrix and acarboxylic acid coupled to the cellulosic fiber matrix.

In yet another aspect, the present disclosure provides an absorbentarticle comprising an absorbent material, wherein the absorbent materialcomprises a fiber matrix and a carboxylic acid coupled to the fibermatrix, wherein the fiber matrix comprises fibers selected from thegroup consisting of cellulose fibers and cellulose-based fibers, andwherein the absorbent article is a feminine hygiene product or a meatpackaging pad.

In another aspect, the present disclosure provides a method of measuringa reduction of free TMA sequestered by an absorbent material comprising:contacting the absorbent material disposed in a container with an amountof TMA; withdrawing a portion of a gas headspace of the container;measuring an amount of free TMA in the withdrawn portion of the gasheadspace; and determining a reduction in free TMA in the gas headspacerelative to a control.

In yet another aspect, the present disclosure provides method of makingan absorbent article comprising: preparing an absorbent materialincluding a fiber matrix and a carboxylic acid coupled to the fibermatrix; and coupling a fluid-permeable top sheet and a fluid-impermeableback sheet to the absorbent material.

DESCRIPTION OF THE DRAWING

The foregoing aspects and many of the attendant advantages of theclaimed subject matter will become more readily appreciated as the samebecome better understood by reference to the following detaileddescription, when taken in conjunction with the accompanying drawing,wherein:

The FIGURE graphically illustrates trimethylamine (TMA) levels in gasheadspaces of containers holding absorbent materials in accordance withembodiments of the present disclosure and controls, each insulted withTMA solutions of different concentrations.

DETAILED DESCRIPTION

Described herein are absorbent materials configured to sequestertrimethylamine (TMA), absorbent articles made therefrom, related methodsof use, methods of measuring free TMA, methods of measuring a reductionof free TMA relative to a control, and related methods of makingabsorbent articles.

The detailed description set forth below, in connection with theappended drawing, is intended as a description of various embodiments ofthe disclosed subject matter and is not intended to represent the onlyembodiments. Each embodiment described in this disclosure is providedmerely as an example or illustration and should not be construed aspreferred or advantageous over other embodiments. The illustrativeexamples provided herein are not intended to be exhaustive or to limitthe claimed subject matter to the precise forms disclosed.

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of one or more embodiments ofthe present disclosure. It will be apparent to one skilled in the art,however, that many embodiments of the present disclosure may bepracticed without some or all of the specific details. In someinstances, well-known process steps have not been described in detail inorder not to unnecessarily obscure various aspects of the presentdisclosure. Further, it will be appreciated that embodiments of thepresent disclosure may employ any combination of features describedherein.

Absorbent Materials

In one aspect, the present disclosure provides an absorbent materialconfigured to sequester TMA. As used herein “sequestration” refers toabsorbing, adsorbing, reducing, binding, neutralizing, and/oreliminating TMA. In this regard, the absorbent materials describedherein are configured to remove TMA from, for example, gas and liquidphases in contact with the absorbent materials by sequestration of theTMA. As discussed further herein, such sequestration reduces levels offree TMA in gas and liquid phases.

In an embodiment, the absorbent materials described herein comprise afiber matrix and a carboxylic acid coupled to the fiber matrix. Asdescribed further herein, many carboxylic acids are water-soluble and,accordingly, may be amenable to aqueous or other solution-basedprocessing to couple the carboxylic acid to the fiber matrix. Certainconventional absorbent materials use powders of non-carboxylic acidcompositions, such as activated charcoal and activated carbon, for odorcontrol. In practice, such powdered odor control components tend toclump, are often combustible, and may become airborne posing acontamination and inhalation risk.

Additionally, many carboxylic acids are readily available andinexpensive rendering them suitable for inclusion in products comprisingabsorbent materials. Furthermore, many carboxylic acids are alsocolorless, and thus may be included into absorbent materials withoutchanging the color of, for example, fiber matrices of the absorbentmaterials. This is in contrast to certain conventional odor controlcomponents that have a dark color, such as activated charcoal andactivated carbon, used in some conventional absorbent articles, whichdarken the color of the absorbent articles.

In an embodiment, the carboxylic acid is a polycarboxylic acid. In anembodiment, the polycarboxylic acid is a partially or fully neutralizedsalt. Without being bound by theory and as discussed further herein withrespect to the figure and EXAMPLE 1, it is believed that the carboxylicacid groups of carboxylic acids aid in sequestration of TMA.Accordingly, because polycarboxylic acids have two or more carboxylicacids groups per carboxylic acid molecule, it is believed that eachpolycarboxylic acid molecule is configured to aid in sequestration ofmore TMA molecules than, for example, a monocarboxylic acid.

In an embodiment, the carboxylic acid is selected from the groupconsisting of malic acid, tartaric acid, salicylic acid, succinic acid,formic acid, pyruvic acid, proprionic acid, butyric acid, isobutyricacid, glycolic acid, salts thereof, and combinations thereof. In yetanother an embodiment, the carboxylic acid is selected from the groupconsisting of citric acid, lactic acid, malic acid, tartaric acid,salicylic acid, succinic acid, formic acid, pyruvic acid, proprionicacid, butyric acid, isobutyric acid, glycolic acid, salts thereof, andcombinations thereof. In another embodiment, the carboxylic acid isselected from the group consisting of citric acid, lactic acid, saltsthereof, and combinations thereof. In an embodiment, the carboxylic acidis citric acid or a salt thereof.

In an embodiment, carboxylic acid salts include carboxylic acid saltsselected from the group consisting of sodium salts, potassium salts,ammonium salts, other metal salts, and combinations thereof.

In an embodiment, the absorbent material comprises a carboxylic acidcontent of between about 0.01 wt % and about 10 wt % (also writtenherein as % by weight). In an embodiment, the absorbent materialcomprises a carboxylic acid content of between about 0.05% by weight andabout 5% by weight. In an embodiment, the absorbent material comprises acarboxylic acid content of between about 0.1% by weight and about 1% byweight. In an embodiment, the absorbent material comprises a carboxylicacid content of about 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%,0.08%, or 0.09% by weight. In an embodiment, the absorbent materialcomprises a carboxylic acid content of about 0.1%, 0.2%, 0.3%, 0.4%,0.5%, 0.6%, 0.7%, 0.8%, or 0.9% by weight. In an embodiment, theabsorbent material comprises a carboxylic acid content of about 1%, 2%,3%, 4%, 5%, 6%, 7%, 8%, or 9% by weight.

Additionally, because the absorbent materials and absorbent articlesdescribed herein sequester TMA, components that mask TMA malodors (suchas fragrances) are not necessary to reduce a TMA malodor. Accordingly,in an embodiment, the absorbent materials described herein do notcomprise a fragrance. Such fragrance-free absorbent materials may beadvantageous for users who, for example, have sensitivities or allergiesto fragrances or prefer not to use products that include fragrances. Itshould also be noted that the absorbent materials and absorbent articlesdescribed herein can react with and sequester other basic moleculeshaving a malodor.

In an embodiment, the fiber matrix comprises a cellulosic pulpstructure. In an embodiment, the cellulosic pulp structure comprises amatrix of cellulose fibers, cellulose-based fibers, or combinationsthereof and a carboxylic acid coupled to the fiber matrix. In anembodiment, the cellulose-based fibers are selected from the groupconsisting of viscose fibers, modal fibers, lyocell fibers, andcombinations thereof. In an embodiment, the fiber matrix comprises afluff pulp. In an embodiment, the fiber matrix comprises a Southernbleached softwood kraft pulp.

In an embodiment, the fiber matrix comprises synthetic fibers. In anembodiment, the fiber matrix comprises non-woven synthetic fibers. In anembodiment, the fiber matrix comprises a mixture of synthetic fibers andnatural fibers.

As discussed further herein, the absorbent materials described hereininclude a carboxylic acid coupled to a fiber matrix. In an embodiment,the carboxylic acid is directly coupled to the fiber matrix without, forexample, a binder, a linker, or other intermediate composition ormolecule between the carboxylic acid and the fiber matrix. In anembodiment, a carboxylic acid coupled to a fiber matrix includes acarboxylic acid covalently bound to the fiber matrix. In an embodiment,a carboxylic acid coupled to a fiber matrix includes a carboxylic acidnon-covalently bound to the fiber matrix. Such non-covalent coupling canoccur by, for example, hydrogen bonding, van der Waals forces, ionicbonds, and combinations thereof.

In an embodiment, the absorbent materials described herein do notcomprise a binder, such as an organosilicone polymeric binder, coupledto the carboxylic acid and binding the carboxylic acid to the fibermatrix. Without being bound by theory, it is believed that thecarboxylic acid is configured, in certain embodiments, to directlycouple with the fiber matrix itself without the need for a binder. Forexample, in certain embodiments, the fiber matrix is a natural fibercomprising hydroxyl groups that couple with the carboxylic acid withouta binder, such as an organosilicone polymeric binder.

In this regard, the absorbent materials and absorbent articles madetherefrom that include a carboxylic acid directly coupled to the fibermatrix also do not require a pouch or other sealed container in order,for example, to contain a powder (such as activated charcoal oractivated carbon) that might otherwise escape from the absorbentmaterial or absorbent article.

In an embodiment, the carboxylic acid is applied to the fiber matrix insolid form, such as in powdered or granular forms. In an embodiment, thesolid carboxylic acid is coupled to the fiber matrix with an adhesive.In an embodiment, the adhesive is a physical adhesive. In an embodiment,adhesive is a chemical adhesive.

In an embodiment, the solid carboxylic acid is applied to a fiber matrixthat has a water content at or greater than the fiber saturation point(“FSP”), which is typically about 20% to about 25% water by weight.Without being bound by theory, it is believed that, in certainembodiments, the solid carboxylic acid at least partially dissolves whencontacted with the wet fiber matrix and couples to the wet fiber matrix.Thus, water content from about 20% to about 99.9% water by weight forthe fiber matrix in this embodiment is sufficient for at least partiallydissolving the solid carboxylic acid.

In an embodiment, the absorbent materials described herein are free ofor substantially free of an inorganic peroxide (in this case, it will beunderstood that “substantially free of an inorganic peroxide” refers toan amount of inorganic peroxide between 0 wt % and 1 wt % as limited byknown detection methods).

TMA sequestration effects can also be observed by utilizing oxidizedcellulosic fibers, which may be manufactured by a known method (see,e.g., U.S. Pat. No. 8,007,635, incorporated herein by reference in itsentirety).

As above, the absorbent materials of the present disclosure areconfigured to sequester TMA. In an embodiment, the absorbent materialsof the present disclosure are configured to sequester greater than orequal to about 6.15409×10⁻⁵ g of TMA per about 1 g of absorbent materialat a state of equilibrium (in this case, “equilibrium” should beunderstood to mean a time point at which TMA entering the gaseousheadspace of the test apparatus reaches a steady state) at 25° C.,wherein the absorbent material is treated with 0.01% by weight with acarboxylic acid selected from one of the groups provided herein. In anembodiment, the absorbent material is configured to sequester greaterthan or equal to about 6.15409×10⁻⁵ g of TMA per about 1 g of absorbentmaterial at a state of equilibrium at 25° C., wherein the absorbentmaterial is treated with 0.01% by weight with citric acid.

As discussed further herein with respect to the methods of the presentdisclosure, in an embodiment, an amount of TMA sequestered by theabsorbent materials described herein is determined by measuring anamount of TMA in a gas headspace of a closed container holding theabsorbent material and an initial amount of TMA. In an embodiment,determining an amount of free TMA upon sequestration of TMA by theabsorbent material includes contacting a known quantity of the absorbentmaterial disposed in the closed container with an initial, known amountof TMA; withdrawing a portion of the gas headspace from the closedcontainer after the absorbent material has been exposed to the initialamount of TMA and allowed to reach equilibrium within the gas headspace;and measuring the gaseous concentration of TMA in the withdrawn portionof the gas headspace (e.g., in ppm).

In an embodiment, the gas headspace has a volume of less than 1 L. In anembodiment, the gas headspace has a volume of about 0.5 L. In anembodiment, the container is a flexible container.

As discussed further herein, in an embodiment, the amount of TMAsequestered by the absorbent material is measured relative to a controlabsorbent material, such as a control absorbent material that does notcomprise a carboxylic acid coupled to a fiber matrix, as discussedfurther herein with respect to EXAMPLE 1, or, alternatively, a controlsample may be performed with a container that does not include anyabsorbent material (i.e., a null control).

In an embodiment, the absorbent materials described herein areconfigured to sequester TMA from a solution in contact with theabsorbent material and sequester TMA from a gas phase in contact withthe absorbent material. In this regard, the absorbent materials areconfigured to eliminate or reduce TMA malodors by sequestering bothgaseous and dissolved or liquid TMA.

As discussed further herein, the absorbent materials of the presentdisclosure are configured to sequester TMA. In an embodiment, by way ofquantifying the capability of TMA sequestration, the absorbent materialis configured to reduce the gaseous concentration of free TMA within agas headspace of a test apparatus (described in detail below) by 50%relative to a control (see above for discussion of appropriatecontrols). In an embodiment, the absorbent material is configured toreduce the amount of free TMA that enters (or otherwise would enter) thegas headspace by 75% relative to a control. In an embodiment, theabsorbent material is configured to reduce the amount of free TMA thatenters (or otherwise would enter) the gas headspace by 85% relative to acontrol. In an embodiment, the absorbent material is configured toreduce the amount of free TMA that enters (or otherwise would enter) thegas headspace by 90% relative to a control. In an embodiment, theabsorbent material is configured to reduce the amount of free TMA thatenters (or otherwise would enter) the gas headspace by 95% relative to acontrol. In an embodiment, the absorbent material is configured toreduce the amount of free TMA that enters (or otherwise would enter) thegas headspace by 99% relative to a control. In an embodiment, theabsorbent material is configured to reduce the amount of TMA that enters(or otherwise would enter) the gas headspace by substantially 100%relative to a control (in this case, “substantially 100%” should beunderstood to mean an amount between 99% and 100% as limited by thedetection method described herein).

As discussed further herein, in an embodiment, the cellulosic fibermatrix of the absorbent material is capable of reducing free TMA from agas headspace by sequestration of the TMA. In an embodiment, thecellulosic fiber matrix of the absorbent material is capable of reducingfree TMA by at least about 95 ppm in a gas headspace of about 0.5 L whenthe absorbent material comprises 0.45% by weight citric acid, the TMA isintroduced in a liquid solution of about 0.034% by weight, and thecontrol is an absorbent material consisting of a southern bleachedsoftwood kraft fluff pulp of equal amount substantially free of anyadded carboxylic acids. In this case, “an equal amount” should beunderstood that to mean an amount of control fluff pulp having a mass ofbetween 95% and 105% of the mass of the absorbent material as limited byknown methods of detection.

In an embodiment, the cellulosic fiber matrix is capable of reducingfree TMA by at least about 99% in a gas headspace of about 0.5 L whenthe absorbent material comprises 0.45%% by weight citric acid, the TMAis introduced in a liquid solution of about 0.027% by weight, and thecontrol is an absorbent material consisting of a southern bleachedsoftwood kraft fluff pulp of equal amount substantially free of anyadded carboxylic acids. In an embodiment, the cellulosic fiber matrix iscapable of reducing free TMA by at least about 50% in a gas headspace ofabout 0.5 L when the absorbent material comprises 0.45%% by weightcitric acid, the TMA is introduced in a liquid solution of about 0.05%by weight, and the control is an absorbent material consisting of asouthern bleached softwood kraft fluff pulp of equal amountsubstantially free of any added carboxylic acids.

As discussed further herein with respect to the methods of reducing anamount of free TMA, in an embodiment, measuring a reduction of free TMAsequestered by an absorbent material of the present disclosure comprisescontacting the absorbent material disposed in a container with an amountof TMA; withdrawing a portion of a gas headspace of the container;measuring an amount of free TMA in the withdrawn portion of the gasheadspace; and determining a reduction in free TMA in the gas headspacerelative to a control.

In an embodiment, the absorbent materials described herein mayoptionally further comprise an additive selected from the groupconsisting of activated charcoal, activated carbon, a fragrance,zeolites, and combinations thereof. While the absorbent materials of thepresent disclosure are configured to sequester TMA without suchadditives, in certain embodiments, the absorbent materials furthercomprise materials, including, but not limited to, activated charcoal,activated carbon, zeolites, or fragrances, configured, for example, tonon-selectively absorb or mask certain other malodors or to supplementother TMA malodor control components of the absorbent materials.

In an embodiment, the absorbent material further comprises asuperabsorbent polymer to aid in absorption of fluids.

Absorbent Articles

In another aspect, the present disclosure provides an absorbent articlecomprising an absorbent material of the present disclosure. As discussedfurther herein, odor control and prevention, particularly associatedwith TMA malodors, in feminine hygiene products and meat packagingproducts is of interest. Because the absorbent materials of the presentdisclosure are configured to sequester TMA they are particularlysuitable for application in feminine hygiene products and meat packagingproducts.

Accordingly, in an embodiment, the absorbent article comprises a fibermatrix and a carboxylic acid coupled to the fiber matrix. In anembodiment, the fiber matrix comprises fibers selected from the groupconsisting of cellulose fibers, cellulose-based fibers, and combinationsthereof.

In an embodiment, the absorbent article comprises a fluid-permeable topsheet. The fluid-permeable top sheet comprises a highly fluid-permeablematerial configured to move liquid, such as from a wearer, to theabsorbent material. In an embodiment, the fluid-permeable top sheetcomprises a material selected from the group consisting of hydrophilicwoven materials, hydrophilic non-woven materials, airlaid sheets,wetlaid sheets, films comprising apertures, open cell foams, andbatting.

In an embodiment, the absorbent article comprises a fluid-impermeableback sheet. The fluid-impermeable back sheet is configured to preventliquid movement from the absorbent material through thefluid-impermeable sheet to, for example, clothing of a wearer.

In an embodiment, the absorbent material forms at least a portion of anabsorbent core of the absorbent article. In an embodiment, the absorbentmaterial is disposed between the fluid-permeable top sheet and thefluid-impermeable back sheet. In an embodiment, the fluid-permeable topsheet and fluid impermeable back sheet are suitably sealed enclosing theabsorbent material. In an embodiment, the absorbent material is disposedwithin the fluid-permeable top sheet.

In an embodiment, the absorbent article is a feminine hygiene product.As described further herein, in an embodiment, the absorbent materialsdescribed herein comprise a fiber matrix and a carboxylic acid coupledto the fiber matrix. In this regard, without being bound by theory, itis believed that the absorbent articles comprising absorbent materialsof the present disclosure reduce TMA malodors associated with vaginalfluids in at least two ways: (1) the carboxylic acid reduces vaginal pH,thereby inhibiting the growth of anaerobic bacteria, and (2) thecarboxylic acid sequesters TMA molecules thereby reducing free TMA, asdiscussed further herein.

In an embodiment, the feminine hygiene product is selected from thegroup consisting of a panty liner, a sanitary napkin, a post-partumabsorbent pad, a light incontinence pad, an interlabial pad, disposablemenstrual protection underwear, and a tampon. In an embodiment, thefeminine hygiene product is selected from the group consisting of apanty liner, a sanitary napkin, a post-partum absorbent pad, a lightincontinence pad, an interlabial pad, and disposable menstrualprotection underwear. In some embodiments, the absorbent articles of thepresent disclosure are not in the form of a tampon. Feminine hygieneproducts may be manufactured according to known methods (see for exampleU.S. Pat. No. 9,717,817, which is incorporated herein by reference inits entirety, and patents referenced therein).

In an embodiment, the feminine hygiene product is configured to be wornexternally. As used herein, a feminine hygiene product configured to beworn externally is configured to be worn outside of a vagina. In anembodiment, the feminine hygiene product is not configured to be worninternally. As used herein, a feminine hygiene product configured to beworn internally is a feminine hygiene product configured to be worn atleast partially within the vagina.

In an embodiment, the absorbent material in the feminine hygiene productcomprises an absorbent material comprising a fiber matrix and acarboxylic acid coupled to the fiber matrix, wherein the absorbentmaterial comprises a carboxylic acid content of between about 0.01 wt %and about 10 wt %.

In an embodiment, the absorbent article is a meat packaging pad. Meatpackaging pads may include those known in the art and be manufacturedaccording to known methods (see for example U.S. Pat. Nos. 5,908,649 and7,655,829, which are incorporated herein by reference in theirentirety). As described further herein, TMA malodors emanate from meatproducts, such as fish products, and there is a need to sequester TMA inmeat packaging products. Because the absorbent materials describedherein are configured to sequester TMA, they are particularly suitablefor use in meat packaging products. In an embodiment, the meat packagingproduct is a meat packaging pad. In an embodiment, the meat packagingpad is a fish packaging pad. In an embodiment, the meat packaging padincluding the absorbent material of the present disclosure is configuredto absorb meat juices, such as fish juices, and other liquids, as wellas sequester TMA.

In an embodiment, the absorbent material in the meat packaging padcomprises a fiber matrix and a carboxylic acid coupled to the fibermatrix, and wherein the absorbent material comprises a carboxylic acidcontent of between about 0.01 wt % and about 10 wt %. In an embodiment,the meat packaging pad comprises a superabsorbent polymer to aid inabsorption of fluids. In an embodiment, the superabsorbent polymer isdisposed within the absorbent material.

Method of Reducing Free TMA

As described further herein, TMA molecules, and TMA malodors arisingtherefrom, from, for example, vaginal fluids or meat juices, may bereduced through the sequestration of TMA by the absorbent materials orabsorbent articles of the present disclosure. By sequestering TMA intothe absorbent material or absorbent articles made therefrom, TMA malodoris reduced relative to an analogous scenario in which the TMA is notsequestered such that, for example, free TMA is present at a level thatit cannot be smelled by a human nose or it can be smelled by a humannose at a greatly reduced level.

Accordingly, in another aspect, the present disclosure provides a methodof reducing free TMA. As used herein, “free TMA” refers to an amount ofTMA that is in a gas headspace or would equilibrate into a gas headspaceand is capable of being measured and/or capable of being smelled by ahuman nose. Free TMA is in contrast to TMA molecules that aresequestered by, for example, an absorbent material or absorbent article,and, therefore, not available for measuring or detection by a humannose.

In an embodiment, the method of reducing levels of free TMA comprisescontacting a TMA molecule with an absorbent material comprising acellulosic fiber matrix and a carboxylic acid coupled to the cellulosicfiber matrix. In an embodiment, the method further comprisessequestering the TMA molecule.

As described further herein, the absorbent materials of the presentdisclosure and absorbent articles made therefrom are configured tosequester TMA from either or both a liquid phase and/or a gas phase.Accordingly, in an embodiment, contacting TMA with the absorbentmaterial or the absorbent article comprises contacting TMA in a solutionphase, such as TMA dissolved in vaginal fluids, menses, or meat juices.In an embodiment, the TMA molecule is in a liquid. In an embodiment, theliquid TMA is a TMA molecule dissolved in a solution or in a suspension.In an embodiment, the liquid TMA is a neat TMA liquid. In an embodiment,contacting TMA with the absorbent material or the absorbent articlecomprises contacting a menstrual fluid containing TMA with the absorbentmaterial or the absorbent article. In an embodiment, contacting TMA withthe absorbent material or the absorbent article comprises contacting ameat fluid, such as a fish fluid, containing TMA with the absorbentmaterial or the absorbent article.

Correspondingly, in an embodiment, contacting TMA with the absorbentmaterial or the absorbent article comprises contacting TMA in a gasphase, such as TMA volatilization from vaginal fluids, menses, or meatjuices.

In an embodiment, the absorbent material is any absorbent materialdescribed herein. In an embodiment, the absorbent article is anyabsorbent article described herein. In an embodiment, the fiber matrixis a cellulosic fiber matrix (see below).

In an embodiment, the carboxylic acid is selected from the groupconsisting of malic acid, tartaric acid, salicylic acid, succinic acid,formic acid, pyruvic acid, proprionic acid, butyric acid, isobutyricacid, glycolic acid, salts thereof, and combinations thereof. In anembodiment, the carboxylic acid is selected from the group consisting ofcitric acid, lactic acid, malic acid, tartaric acid, salicylic acid,succinic acid, formic acid, pyruvic acid, proprionic acid, butyric acid,isobutyric acid, glycolic acid, salts thereof, and combinations thereof.In an embodiment, the carboxylic acid is citric acid or a salt thereof.

In an embodiment, the absorbent material comprises a carboxylic acidcontent of between about 0.01% by weight and about 10% by weight. In anembodiment, the absorbent material comprises a carboxylic acid contentof between about 0.05% by weight and about 5% by weight. In anembodiment, the absorbent material comprises a carboxylic acid contentof between about 0.1% by weight and about 1% by weight. In anembodiment, the absorbent material comprises a carboxylic acid contentof about 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, or0.09% by weight. In an embodiment, the absorbent material comprises acarboxylic acid content of about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%,0.7%, 0.8%, or 0.9% by weight. In an embodiment, the absorbent materialcomprises a carboxylic acid content of about 1%, 2%, 3%, 4%, 5%, 6%, 7%,8%, or 9% by weight.

In an embodiment, the fiber matrix comprises a cellulosic pulpstructure. In an embodiment, the cellulosic pulp structure comprises amatrix of cellulose fibers, cellulose-based fibers, or combinationsthereof and a carboxylic acid coupled to the fiber matrix. In anembodiment, the cellulose-based fibers are selected from the groupconsisting of viscose fibers, modal fibers, lyocell fibers, andcombinations thereof. In an embodiment, the fiber matrix comprises afluff pulp. In an embodiment, the fiber matrix comprises a Southernbleached softwood kraft pulp.

In an embodiment, the fiber matrix comprises synthetic fibers. In anembodiment, the fiber matrix comprises non-woven synthetic fibers. In anembodiment, the fiber matrix comprises a mixture of synthetic fibers andnatural fibers.

In an embodiment, contacting TMA with an absorbent material or anabsorbent article made therefrom reduces at least 50% of the free TMAavailable to leave or re-enter into the absorbent material or absorbentarticle as a gaseous compound. In an embodiment, contacting TMA with anabsorbent material or an absorbent article made therefrom reduces atleast 75% of the free TMA available to leave or re-enter into theabsorbent material or absorbent article as a gaseous compound. In anembodiment, contacting TMA with an absorbent material or an absorbentarticle made therefrom reduces at least 85% of the free TMA available toleave or re-enter into the absorbent material or absorbent article. Inan embodiment, contacting TMA with an absorbent material or an absorbentarticle made therefrom reduces at least 95% of the free TMA available toleave or re-enter into the absorbent material or absorbent article. Inan embodiment, contacting TMA with an absorbent material or an absorbentarticle made therefrom reduces at least 99% of the free TMA available toleave or re-enter into the absorbent material or absorbent article.

Method of Measuring a Reduction in Free TMA

In another aspect, the present disclosure provides a method of measuringa reduction of free TMA sequestered by an absorbent material, such as anabsorbent material of the present disclosure or an absorbent articlemade therefrom. In an embodiment, the absorbent material is disposed ina closed container and is contacted with an amount of TMA. After theabsorbent material has had an opportunity to sequester at least aportion of the amount TMA and, for example, the amount of TMA hasreached an equilibrium between a gas headspace of the closed containerand the absorbent material, a portion of the gas headspace is withdrawnfrom the closed container. In an embodiment, the amount of TMA isallowed to contact the absorbent material for sufficient time to reachequilibrium before a portion of the gas headspace is withdrawn from theclosed container, thereby also providing sufficient time for at least aportion of the initial amount of TMA to be sequestered within theabsorbent material. A person of ordinary skill in the art would readilyknow how to generate an equilibrium curve or other appropriate tool tomonitor for and identify equilibrium.

In an embodiment, the closed container is a flexible containerconfigured to at least partially collapse in response to the portion ofthe gas headspace being withdrawn. In this regard, it is easier for auser to withdraw the portion of the gas headspace from the closedcontainer.

The withdrawn portion of the gas headspace is assayed to determine agaseous concentration of free TMA present in the headspace. In anembodiment, measuring the amount of free TMA in the withdrawn portioncomprises passing the withdrawn portion of the gas headspace over astationary phase loaded with a colorimetric marker that changes colorwhen contacted with TMA; and measuring an amount of color change in thestationary phase in response to passing the withdrawn portion of the gasheadspace over the stationary phase. In an embodiment, assaying thewithdrawn portion of the gas headspace to measure the gaseousconcentration of free TMA comprises using a colorimetric gas detectortube, such as a Sensidyne® gas detector tube system. While colorimetricdetection methods are described, it will be understood that othermethods of TMA detection, for example, and not limited to, gaschromatography, can be used consistent with the methods of the presentdisclosure.

Reduction of free TMA is measured relative to a control. In anembodiment, the control is a null control, where a null control includesa control that does not include contacting a TMA molecule with anabsorbent material. In an embodiment, the control is an absorbentmaterial control, where an absorbent material control is an absorbentmaterial having substantially no or no added carboxylic acid coupled toa fiber matrix (in this case, “substantially no added carboxylic acid”or “substantially free of added carboxylic acid” should be understood tomean no added carboxylic acid or an amount of added carboxylic acidbetween 0 wt % and 1 wt % as limited by known detection methods). Asused herein, “added carboxylic acid” should be understood to mean anamount of carboxylic acid added or otherwise coupled to an absorbentmaterial during processing or manufacturing over and above anycarboxylic present in an untreated absorbent material. In an embodiment,the control absorbent material comprises a fluff pulp, such as aSouthern bleached softwood kraft pulp, that has not been treated with orotherwise coupled to a carboxylic acid. In this regard, a user candetermine an amount of TMA reduction by the carboxylic acid coupled tothe fiber matrix of the absorbent materials described herein relative tothe chosen control.

In an embodiment, an amount of TMA not sequestered by the absorbentmaterial and allowed to equilibrate within the gaseous headspace(TMA_(g)) is compared to an amount of TMA not sequestered in a controlexperiment that is allowed to equilibrate within the control gaseousheadspace (TMA_(c)). The reduction in gaseous concentration of free TMAmeasured in the headspace above the absorbent material relative to thatof a control may be expressed as percent reduction of free TMA (%TMA_(red)). This percent reduction can be calculated with the followingequation.

${\%\mspace{14mu}{TMA}_{red}} = {\frac{{TMA}_{c} - {TMA}_{g}}{{TMA}_{c}} \times 100\%}$

It should be noted that fluid containing TMA, such as a fluid used toinsult an absorbent material or absorbent article, that resides on aside or other portion of the closed container may skew TMA reductionresults. Such TMA-containing fluid that does not contact an absorbentmaterial or absorbent article may result in increased volatilization ofTMA from the TMA-containing solution into the gas headspace of theclosed container. Such increased TMA volatilization may result in higherrelative gaseous TMA concentrations than if the TMA-containing solutionwere insulted directly onto the absorbent material or absorbent articleincorrectly indicating a capability (or lack thereof) of the absorbentmaterial or absorbent article to sequester TMA.

Method of Sequestering TMA

As described further herein, the absorbent material and absorbentarticles made therefrom are capable of sequestering TMA. Accordingly, inanother aspect, the present disclosure provides a method of sequesteringa TMA molecule. In an embodiment, the method of sequestering a TMAcomprises contacting the TMA molecule with an absorbent materialcomprising a fiber matrix and a carboxylic acid coupled to the fibermatrix or an absorbent article made therefrom. In an embodiment, themethod further comprises sequestering the TMA molecule in the absorbentmaterial or absorbent article made therefrom.

In an embodiment, the absorbent material is any absorbent materialdescribed herein. In an embodiment, the absorbent article is anyabsorbent article described herein. In an embodiment, the fiber matrixis a cellulosic fiber matrix. In an embodiment, the cellulosic fibermatrix comprises a cellulosic pulp structure. In an embodiment, thecellulosic fiber matrix comprises fibers selected from the groupconsisting of cellulose fibers and cellulose-based fibers. In anembodiment, the cellulose-based fibers are selected from the groupconsisting of viscose fibers, modal fibers, lyocell fibers, andcombinations thereof.

In an embodiment, the carboxylic acid is selected from the groupconsisting of malic acid, tartaric acid, salicylic acid, succinic acid,formic acid, pyruvic acid, proprionic acid, butyric acid, isobutyricacid, glycolic acid, salts thereof, and combinations thereof. In anembodiment, the carboxylic acid is selected from the group consisting ofcitric acid, lactic acid, malic acid, tartaric acid, salicylic acid,succinic acid, formic acid, pyruvic acid, proprionic acid, butyric acid,isobutyric acid, glycolic acid, salts thereof, and combinations thereof.In an embodiment, the carboxylic acid is citric acid or a salt thereof.

In an embodiment, the absorbent material comprises a carboxylic acidcontent of between about 0.01% by weight and about 10% by weight. In anembodiment, the absorbent material comprises a carboxylic acid contentof between about 0.05% by weight and about 5% by weight. In anembodiment, the absorbent material comprises a carboxylic acid contentof between about 0.1% by weight and about 1% by weight. In anembodiment, the absorbent material comprises a carboxylic acid contentof about 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, or0.09% by weight. In an embodiment, the absorbent material comprises acarboxylic acid content of about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%,0.7%, 0.8%, or 0.9% by weight. In an embodiment, the absorbent materialcomprises a carboxylic acid content of about 1%, 2%, 3%, 4%, 5%, 6%, 7%,8%, or 9% by weight.

In an embodiment, contacting the TMA molecule with the absorbentmaterial or the absorbent article comprises contacting a liquid, such asa menstrual fluid, containing TMA with the absorbent material or theabsorbent article made therefrom. In an embodiment, contacting the TMAmolecule with the absorbent material comprises contacting a meat fluidcontaining the TMA molecule with the absorbent material or the absorbentarticle made therefrom. In an embodiment, the TMA molecule is in a gasphase, which contacts the absorbent material or absorbent article.

In an embodiment, the fiber matrices of the absorbent material of thepresent disclosure and absorbent articles made therefrom are capable ofsequestering the TMA molecules such that a gas headspace of about 0.5 Lat equilibrium contains less than about 1 ppm, 2 ppm, 3 ppm, 4 ppm, 5ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, or 50 ppm of free TMA when theabsorbent material comprises 0.45% by weight citric acid. In anembodiment, the fiber matrices of the absorbent material of the presentdisclosure and absorbent articles made therefrom are capable ofsequestering the TMA molecules such that a gas headspace of about 0.5 Lat equilibrium contains less than about 50 ppm of free TMA atequilibrium when the absorbent material comprises 0.01% by weight citricacid and the TMA molecules are introduced in a liquid solution ofbetween about 0.0005% by weight and about 0.034% by weight. In anembodiment, the fiber matrices of the absorbent material of the presentdisclosure and absorbent articles made therefrom are capable ofsequestering the TMA molecules such that a gas headspace of about 0.5 Lat equilibrium contains less than about 50 ppm of free TMA when theabsorbent material comprises 0.01% by weight citric acid and the TMAmolecules are introduced in a liquid solution of about 0.0005%, 0.001%,0.005%, 0.01%, 0.015%, 0.02%, 0.025%, 0.027%, 0.03%, 0.034%, or 0.035%by weight. In an embodiment, the cellulosic fiber matrix is capable ofsequestering the TMA molecules such that a gas headspace of about 0.5 Lat equilibrium contains less than about 10 ppm of free TMA when theabsorbent material comprises 0.01% by weight citric acid and the TMAmolecules are introduced in a liquid solution of about 0.034% by weight.In an embodiment, the cellulosic fiber matrix is capable of sequesteringthe TMA molecules such that a gas headspace of about 0.5 L atequilibrium contains less than about 5 ppm of free TMA when theabsorbent material comprises 0.01% by weight citric acid and the TMAmolecules are introduced in a liquid solution of about 0.027% by weight.

In an embodiment, the cellulosic fiber matrix is capable of reducingfree TMA by at least about 95 ppm in a gas headspace of about 0.5 L whenthe absorbent material comprises 0.01% by weight citric acid, the TMA isintroduced in a liquid solution of about 0.034% by weight, and thecontrol is an absorbent material consisting of a southern bleachedsoftwood kraft fluff pulp of equal amount substantially free of anyadded carboxylic acids.

In an embodiment, wherein the cellulosic fiber matrix is capable ofreducing free TMA by at least about 99% in a gas headspace of about 0.5L when the absorbent material comprises 0.01% by weight citric acid, theTMA is introduced in a liquid solution of about 0.027% by weight, andthe control is an absorbent material consisting of a southern bleachedsoftwood kraft fluff pulp of equal amount substantially free of anyadded carboxylic acids. In an embodiment, the cellulosic fiber matrix iscapable of reducing free TMA by at least about 50% in a gas headspace ofabout 0.5 L when the absorbent material comprises 0.01% by weight citricacid, the TMA is introduced in a liquid solution of about 0.05% byweight, and the control is an absorbent material consisting of asouthern bleached softwood kraft fluff pulp of equal amountsubstantially free of any added carboxylic acids.

In an embodiment, determining an amount of free TMA after TMA has beensequestered by the absorbent materials described herein includescontacting the absorbent material disposed in a container with aninitial amount of TMA in a liquid solution; withdrawing a portion of agas headspace of the container; measuring an amount of free TMA in thewithdrawn portion of the gas headspace, e.g., in ppm units. Themeasuring step can be performed in any suitable manner, including solidphase colorimetric gas detection tube described herein, gaschromatography, or others. Without being bound by theory, it is believedthat TMA in a liquid solution in contact with the absorbent materialswill react with the carboxylic acid and be reduced to a salt of aRCOO⁻N⁺(Me)₃, thus sequestering TMA by decreasing the available TMA forvolatilization and equilibrating into the gas headspace of theexperimental container apparatus, and thereby eliminating the TMAmalodor.

Method of Making an Absorbent Article

As described further herein, the absorbent materials of the presentdisclosure and absorbent articles made therefrom are suitable as, forexample, absorbent cores or other absorbent portions of absorbentarticles, such as feminine hygiene products, because of their ability tosequester TMA. Accordingly, in another aspect, the present disclosureprovides a method of making an absorbent article, such as a femininehygiene product and a meat packaging pad, comprising an absorbentmaterial of the present disclosure. In an embodiment, the methodcomprises preparing an absorbent material including a fiber matrix and acarboxylic acid coupled to the fiber matrix; and coupling afluid-permeable top sheet and a fluid-impermeable back sheet to theabsorbent material. In an embodiment, preparing an absorbent materialcomprises forming a cellulosic pulp structure by forming a cellulosepulp sheet from a cellulose pulp slurry, and forming a matrix ofcellulose fibers from the cellulose pulp sheet. In an embodiment, acarboxylic acid is added by applying the acid in aqueous form to thepulp sheet. As also described further herein, in an embodiment, thecarboxylic acid is added in a solid form, such as with a binder oradhesive.

In an embodiment, the absorbent material is any absorbent materialdescribed herein including a fiber matrix and a carboxylic acid coupledto the fiber matrix. In an embodiment, the fluid-permeable top sheet isany fluid-permeable top sheet described herein. In an embodiment, thefluid-impermeable back sheet is any fluid-impermeable back sheetdescribed herein.

In an embodiment, the fluid-permeable top sheet and thefluid-impermeable back sheet are coupled to the absorbent material by acoupling method selected from the group consisting of stitching,coupling with an adhesive, heat sealing, ultrasonic welding, andcombinations thereof.

In an embodiment, the fluid-permeable top sheet and thefluid-impermeable back sheet are coupled around the absorbent materialand the absorbent material is disposed between the fluid-permeable topsheet and the fluid-impermeable back sheet. In this regard, theabsorbent material forms at least a portion of an absorbent core of theabsorbent article. In an embodiment, the absorbent material is disposedwithin the fluid-permeable top sheet.

In an embodiment, the feminine hygiene product is selected from thegroup consisting of a panty liner, a sanitary napkin, a post-partumabsorbent pad, a light incontinence pad, an interlabial pad, disposablemenstrual protection underwear, and a tampon. In an embodiment, thefeminine hygiene product is selected from the group consisting of apanty liner, a sanitary napkin, a post-partum absorbent pad, a lightincontinence pad, an interlabial pad, and disposable menstrualprotection underwear. In some embodiments, the absorbent articles of thepresent disclosure are not in the form of a tampon. Feminine hygieneproducts may be manufactured according to known methods (see for exampleU.S. Pat. No. 9,717,817, which is incorporated herein by reference inits entirety).

In an embodiment, the feminine hygiene product is configured to be wornexternally. In an embodiment, the feminine hygiene product is notconfigured to be worn internally.

In an embodiment, the absorbent article is a meat packaging pad. In anembodiment, the meat packaging pad is a fish packaging pad. Meatpackaging pads may include those known in the art and be manufacturedaccording to known methods (see for example U.S. Pat. Nos. 5,908,649 and7,655,829, which are incorporated herein by reference in theirentirety).

EXAMPLES Example 1: Sequestration of TMA with a Fluff Pulp Treated withCitric Acid

Fluff pulp treated with citric acid (0.45 wt %) and untreated fluff pulpwere fiberized, formed into pads, placed in sealed containers, andinsulted with TMA solution. The untreated fluff pulp is from the samemill as the fluff pulp treated with citric, but does not contain thebuffering treatment.

Fluff pulp sheets were fiberized and the fluff pulp was then formed into2-inch diameter pads with an average weight of 0.94±0.02 g. These padswere compressed in a press to a pressure of 2000 psi.

Testing containers were constructed from 500 mL water bottles, whichwere selected due to their compressibility. 16 gauge needles were driventhrough plastic lids of the water bottles, glued in place, and sealedwith silicone caulking. Rubber tubing was placed around the hilt of theneedles to allow for an airtight seal between the hilt and measurementdevices.

The compressed fluff rounds were introduced into the testing containers,insulted with 15 g of solution, sealed, and then the headspace above wastested for TMA after 2 hours. TMA solutions were tested at fourconcentrations: 0.0005%, 0.027%, 0.034%, and 0.05% by weight. Normalvaginal fluid not associated with bacterial vaginosis has TMA levels0.0005% by weight according to literature values.

TABLE 1 TMA solutions % by weight TMA g DI water μL 25% solutionsolutions literature value for 1000 20 0.0005 healthy vaginal fluid  58xliterature 300.2 347 0.027  73x literature 300.02 439 0.034 106xliterature 300 639 0.05

The concentration of TMA in the headspace of the containers was testedabove both control and test pulps two hours after insult. 105SE modelSensidyne® tubes were used. These tubes are labelled for use withammonia, but are able to be used with TMA, as well. The actual TMAconcentration is found by multiplying the Sensidyne® reading by aconversion factor of 0.5.

Twenty-five total samples were tested: eleven untreated control fluffpulp samples and fourteen test fluff pulp samples treated with citricacid. A minimum of two samples per concentration were averaged. Three ormore samples per concentration were tested when the first two resultsvaried. The twenty-five samples were allowed to interact with the TMAinsult for approximately two hours at 25° C. to ensure equilibrationbefore TMA in the container gas headspace was measured.

The TMA concentrations in headspaces above pads were compared for thetest fluff pulp treated with citric acid and untreated control fluffpulp. It was found that the fluff pulp treated with citric aciddecreased the headspace concentration of TMA in varying amounts, assummarized in TABLE 2 and the figure. As shown, the citric acid-treatedfluff was found to eliminate TMA volatilization at literatureconcentrations in healthy vaginal fluid, at 0.0005% by weight, as wellas at sixty times this concentration at 0.027% by weight. At 0.034% byweight, seventy times literature value, citric acid-treated fluff wasfound to reduce odorant volatilization into headspace 95% on average.The ability of citric acid-treated fluff to consistently inhibit TMAvolatilization into headspace was not overwhelmed until a concentrationof TMA 100 times that found in healthy vaginal fluid, at 0.05% byweight. Even at this concentration, the citric acid-treated fluff had aheadspace odorant level on average 71.1% less than that of untreatedfluff.

TABLE 2 Reduction of Free TMA in Headspace After Contact with Treatedand Untreated Fluff Pulps. Average Concentration of TMA in Headspace (#of samples) in ppm % Reduction = % wt TMA Solution Treated fluffUntreated fluff$\frac{{Untreated} - {{treated}\mspace{14mu}{fluff}}}{Untreated}*100\%$0.0005   0 (2)   0 (2) N/A 0.027 0.33 (3) 71.7 (3) 99.5% 0.034 4.83 (3) 100 (3) 95.2% 0.05 26.8 (5) 92.7 (3) 71.1%

At 0.027% TMA solution, the average concentration of TMA in theheadspace for the citric acid-treated fluff pads was 0.33 ppm. Untreatedpulp had an average concentration of TMA in the headspace of 72 ppm TMA.The citric acid-treated fluff reduced the TMA in the headspace by 99.5%.

At 0.034% TMA solution, citric acid-treated fluff had an averageconcentration of TMA in the headspace reading of 5 ppm; untreated pulphad an average TMA level of 100 ppm in the gas headspace. It is notedthat the detection limit of the Sensidyne® tubes is 100 ppm.Accordingly, the actual average TMA level in the gas headspace may havebeen higher than 100 ppm. The citric acid-treated fluff reduced TMA inheadspace readings by at least 95%.

At 0.05% solution, citric acid-treated fluff had an averageconcentration of TMA in the headspace reading of 26.8 ppm. However,citric acid-treated fluff readings at this concentration ranged from 10to 51 ppm. In contrast, the largest variation between any other twosample points at the other concentrations was 7 ppm (between 68 ppm and75 ppm for untreated pulp at 0.03%).

The TMA concentrations in headspace above untreated fluff were above themaximum reading of the sensor for two of the three readings taken. As itis not possible to know the exact concentration, these data have beenreported as a 100 ppm sensor reading. An estimation may be made for howmuch higher than the maximum reading the actual concentration is, basedon how quickly the sensor reaches its maximum value, how far past themaximum the colorimetric reading has stopped, and on the malodorencountered by the tester (TMA has a fishy malodor at lowconcentrations, but an ammonia-like odor at high concentrations), butthis is merely an estimation. These observations have been recorded inthe test records.

It should be noted that for purposes of this disclosure, terminologysuch as “upper,” “lower,” “vertical,” “horizontal,” “inwardly,”“outwardly,” “inner,” “outer,” “front,” “rear,” etc., should beconstrued as descriptive and not limiting the scope of the claimedsubject matter. Further, the use of “including,” “comprising,” or“having” and variations thereof herein is meant to encompass the itemslisted thereafter and equivalents thereof as well as additional items.Unless limited otherwise, the terms “connected,” “coupled,” and“mounted” and variations thereof herein are used broadly and encompassdirect and indirect connections, couplings, and mountings. The term“about” means plus or minus 5% of the stated value.

The principles, representative embodiments, and modes of operation ofthe present disclosure have been described in the foregoing description.However, aspects of the present disclosure which are intended to beprotected are not to be construed as limited to the particularembodiments disclosed. Further, the embodiments described herein are tobe regarded as illustrative rather than restrictive. It will beappreciated that variations and changes may be made by others, andequivalents employed, without departing from the spirit of the presentdisclosure. Accordingly, it is expressly intended that all suchvariations, changes, and equivalents fall within the spirit and scope ofthe present disclosure, as claimed.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
 1. A method of reducing free trimethylamine (“TMA”) comprising contacting a TMA molecule with an absorbent material comprising a cellulosic fiber matrix and a carboxylic acid coupled to the cellulosic fiber matrix, wherein the reduction in free TMA is relative to a control.
 2. The method of claim 1, wherein the TMA molecule is in a liquid.
 3. The method of claim 2, wherein the TMA molecule is in a menstrual fluid.
 4. The method of claim 2, wherein the TMA molecule is in a meat fluid.
 5. The method of claim 1, wherein the TMA molecule is in a gas.
 6. The method of claim 1, wherein the control is a null control.
 7. The method of claim 1, wherein the control is an absorbent material control.
 8. The method of claim 1, wherein the cellulosic fiber matrix comprises a cellulosic pulp structure.
 9. The method of claim 1, wherein the cellulosic fiber matrix comprises fibers selected from the group consisting of cellulose fibers and cellulose-based fibers.
 10. The method of claim 9, wherein the cellulose-based fibers are selected from the group consisting of viscose fibers, modal fibers, lyocell fibers, and combinations thereof.
 11. The method of claim 1, wherein the carboxylic acid is selected from the group consisting of malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, proprionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof.
 12. The method of claim 1, wherein the carboxylic acid is selected from the group consisting of citric acid, lactic acid, malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, proprionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof.
 13. The method of claim 1, wherein the carboxylic acid is citric acid or a salt thereof.
 14. The method of claim 1, wherein the absorbent material comprises a carboxylic acid content of between about 0.01% by weight and about 10% by weight.
 15. The method of claim 1, wherein the cellulosic fiber matrix is capable of reducing free TMA by at least about 95 ppm in a headspace of about 0.5 L when the absorbent material comprises 0.01% by weight citric acid, the TMA is introduced in a liquid solution of about 0.034% by weight, and the control is an absorbent material consisting of a southern bleached softwood kraft fluff pulp of equal amount substantially free of any added carboxylic acids.
 16. The method of claim 1, wherein the cellulosic fiber matrix is capable of reducing free TMA by at least about 99% in a headspace of about 0.5 L when the absorbent material comprises 0.01% by weight citric acid, the TMA is introduced in a liquid solution of about 0.027% by weight, and the control is an absorbent material consisting of a southern bleached softwood kraft fluff pulp of equal amount substantially free of any added carboxylic acids.
 17. The method of claim 1, wherein the cellulosic fiber matrix is capable of reducing free TMA by at least about 50% in a headspace of about 0.5 L when the absorbent material comprises 0.01% by weight citric acid, the TMA is introduced in a liquid solution of about 0.05% by weight, and the control is an absorbent material consisting of a southern bleached softwood kraft fluff pulp of equal amount substantially free of any added carboxylic acids.
 18. The method of claim 1, wherein the reduction in free TMA is measured by a process comprising: contacting the absorbent material disposed in a container with an amount of TMA; withdrawing a portion of a gas headspace of the container; measuring an amount of free TMA in the withdrawn portion of the gas headspace; and determining a reduction in free TMA in the gas headspace relative to a control.
 19. A method of sequestering TMA molecules comprising contacting the TMA molecule with an absorbent material comprising a cellulosic fiber matrix and a carboxylic acid coupled to the cellulosic fiber matrix.
 20. The method of claim 19, wherein the TMA molecules are in a liquid.
 21. The method of claim 20, wherein the TMA molecules are in a menstrual fluid.
 22. The method of claim 20, wherein the TMA molecules are in a meat fluid.
 23. The method of claim 19, wherein the TMA molecules are in a gas.
 24. The method of claim 19, wherein the cellulosic fiber matrix comprises a cellulosic pulp structure.
 25. The method of claim 19, wherein the cellulosic fiber matrix comprises fibers selected from the group consisting of cellulose fibers and cellulose-based fibers.
 26. The method of claim 25, wherein the cellulose-based fibers are selected from the group consisting of viscose fibers, modal fibers, lyocell fibers, and combinations thereof.
 27. The method of claim 19, wherein the carboxylic acid is selected from the group consisting of malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, proprionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof.
 28. The method of claim 19, wherein the carboxylic acid is selected from the group consisting of citric acid, lactic acid, malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, proprionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof.
 29. The method of claim 19, wherein the carboxylic acid is citric acid or a salt thereof.
 30. The method of claim 19, wherein the absorbent material comprises a carboxylic acid content of between about 0.01% by weight and about 10% by weight.
 31. The method of claim 19, wherein the cellulosic fiber matrix is capable of sequestering the TMA molecules such that a headspace of about 0.5 L at equilibrium contains less than about 50 ppm of free TMA when the absorbent material comprises 0.45%% by weight citric acid and the TMA molecules are introduced in a liquid solution of about 0.05% by weight.
 32. The method of claim 19, wherein the cellulosic fiber matrix is capable of sequestering the TMA molecules such that a headspace of about 0.5 L at equilibrium contains less than about 10 ppm of free TMA when the absorbent material comprises 0.45% by weight citric acid and the TMA molecules are introduced in a liquid solution of about 0.034% by weight.
 33. The method of claim 19, wherein the cellulosic fiber matrix is capable of sequestering the TMA molecules such that a headspace of about 0.5 L at equilibrium contains less than about 5 ppm of free TMA when the absorbent material comprises 0.45% by weight citric acid and the TMA molecules are introduced in a liquid solution of about 0.027% by weight.
 34. The method of claim 31, wherein the amount of free TMA is measured by a process comprising: contacting the absorbent material disposed in a container with an amount of TMA in a liquid solution; withdrawing a portion of a gas headspace of the container; and measuring an amount of free TMA in the withdrawn portion of the gas headspace. 